Solution polymerization processes are typically carried out at temperatures that are above the melting point of the ethylene homopolymer or copolymer product. In a typical solution polymerization process, catalyst components, solvent, monomers and hydrogen are fed under pressure to one or more reactors.
For ethylene polymerization, or ethylene copolymerization, reactor temperatures can range from about 80° C. to about 300° C. while pressures generally range from about 3 MPag to about 45 MPag. The ethylene homopolymer or copolymer produced remains dissolved in the solvent under reactor conditions. The residence time of the solvent in the reactor is relatively short, for example, from about 1 second to about 20 minutes. The solution process can be operated under a wide range of process conditions that allow the production of a wide variety of ethylene polymers. Post reactor, the polymerization reaction is quenched to prevent further polymerization, by adding a catalyst deactivator, and passivated, by adding an acid scavenger. Once passivated, the polymer solution is forwarded to a polymer recovery operation where the ethylene homopolymer or copolymer is separated from process solvent, unreacted residual ethylene and unreacted optional α-olefin(s).
There is a need to improve the continuous solution polymerization process, for example, to increase the production rate (kilograms of ethylene homopolymer or copolymer produced per hour) and to improve energy efficiency by reducing the amount of energy consumed and greenhouse gas emissions.